The Animal Research Core will provide investigators of each project with assistance in the conduct of research involving mice. To do this, the core will perform the following: 1. Maintain mouse breeding colonies and a database containing relevant information. Data on strain designation, genotype, date of birth, identity of parents, cage card number, sex, number in cage, transponder identification number, and other information as needed will be entered and maintained in a computerized database. Updated information on each breeding colony will be provided to investigators on a weekly basis. Core personnel will be responsible for daily monitoring of each breeder colony, weaning of littermates, implantation of transponders, and setting up an appropriate number of breeder cages. 2.Genotyping of transgenic and mutant mice. Tail DNA will be isolated and used to perform PCR to determine the genotype of founder transgenic and knockout mice obtained by project investigators from commercial sources or from collaborators, and of animals produced by breeding colonies. 3. Assist in the conduct of animal experiments. Core personnel will coordinate and assist in the performance of standardized procedures during the conduct of animal experiments by investigators in each project. These procedures include implantation of transponders and recording of identification numbers, administration of test substances, obtained serum samples, and killing animals before tissue harvest.